Resin composition, pellets, molded articles, method for improving appearance, and appearance improving agent.

Abstract

The present invention provides a resin composition comprising a thermoplastic resin blended with A glass fibers and / or C glass fibers, such as recycled glass fibers, which exhibits excellent resistance to humid heat and, when molded into a product, has a superior appearance after a humid heat test, as well as pellets, molded products, a method for improving appearance, and an appearance improving agent. [Solution] A resin composition comprising a thermoplastic resin and glass fibers, wherein the glass fibers comprise C glass fibers and / or A glass fibers, and the thermoplastic resin comprises a polyamide resin. A method for improving the appearance of a resin composition comprising a thermoplastic resin and C glass fibers and / or A glass fibers, wherein at least a portion of the thermoplastic resin is made up of a polyamide resin. An appearance improving agent for a resin composition comprising a thermoplastic resin and C glass fibers and / or A glass fibers, the appearance improving agent comprising a polyamide resin.

Description

Technical Field

[0001] The present invention relates to a resin composition, pellets, a molded article, a method for improving appearance, and an appearance improver.

Background Art

[0002] Generally, thermoplastic resins are widely used in electrical and electronic equipment parts, interior and exterior automotive parts, other electrical parts, mechanical parts, etc. because they are excellent in mechanical strength, chemical resistance, etc. In order to improve the mechanical strength such as tensile strength of these thermoplastic resins, they may be used as glass fiber reinforced thermoplastic resin compositions containing glass fibers. In this case, as the glass fiber, glass fiber made of E glass is usually used because it is excellent in heat resistance strength expression (Patent Documents 1 to 3).

[0003] On the other hand, in recent years, from the viewpoint of effective utilization of resources, the recycling of glass fibers has also been studied, and it has been proposed to use recycled glass fibers for the glass fibers used in glass fiber reinforced thermoplastic resin compositions (Patent Document 4).

[0004] Recycled glass fibers are usually produced by melting and spinning glass raw materials containing inexpensive waste glass for glass bottles and building materials. Therefore, unlike virgin glass fibers made of E glass used in conventional glass fiber reinforced thermoplastic resin compositions, recycled glass fibers are composed of inexpensive A glass fibers and C glass fibers.

[0005] Patent Document 4 describes polybutylene terephthalate, polyethylene terephthalate, polycarbonate, and polyphenylene sulfide as preferred thermoplastic resins for the thermoplastic resin of the glass fiber reinforced thermoplastic resin composition using such recycled glass fibers, and polybutylene terephthalate is used in the examples.

Prior Art Documents

Patent Documents

[0006] [Patent Document 1] Japanese Patent Publication No. 2022-080888 [Patent Document 2] Japanese Patent Publication No. 2020-55986 [Patent Document 3] International Publication No. 2020 / 246459 [Patent Document 4] Japanese Patent Publication No. 2024-133149 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] The present inventors investigated conventional glass fiber-reinforced thermoplastic resin compositions using recycled glass fibers and found that molded articles of glass fiber-reinforced thermoplastic resin compositions, which are made by blending recycled glass fibers with thermoplastic resins such as polybutylene terephthalate as described in Patent Document 4, have poor resistance to humid heat and cause appearance defects such as the deposition of powdery material on the surface of the molded article after a humid heat test.

[0008] The present invention aims to solve the aforementioned problems and provides a resin composition comprising A glass fibers and / or C glass fibers, such as recycled glass fibers, in a thermoplastic resin, which exhibits excellent resistance to humid heat and, when molded, has an excellent appearance after a humid heat test, as well as pellets, molded articles, a method for improving appearance, and an appearance improving agent. [Means for solving the problem]

[0009] In order to solve the above problems, the inventors conducted research and found that the above problems can be solved by using polyamide resin as the thermoplastic resin. Specifically, the above problem was solved by the following means.

[0010] [1] A resin composition comprising a thermoplastic resin and glass fibers, The glass fiber includes C glass fiber and / or A glass fiber, A resin composition in which the thermoplastic resin includes a polyamide resin. [2] The resin composition according to [1], wherein the glass fibers include recycled glass fibers. [3] The resin composition according to [1] or [2], comprising 1% by mass or more of sodium oxide and / or potassium oxide in the C glass fiber and / or A glass fiber. [4] Pellets of the resin composition described in any of [1] to [3]. [5] A molded article made from any of the resin compositions described in [1] to [3]. [6] [4] A molded product formed from the pellets described above. [7] A method for improving the appearance of a resin composition comprising a thermoplastic resin and C glass fibers and / or A glass fibers, wherein at least a portion of the thermoplastic resin is a polyamide resin. [8] An appearance enhancer for a resin composition comprising a thermoplastic resin and C glass fibers and / or A glass fibers, the appearance enhancer comprising a polyamide resin. [Effects of the Invention]

[0011] The present invention provides a resin composition comprising a thermoplastic resin blended with A glass fibers and / or C glass fibers, such as recycled glass fibers, which exhibits excellent resistance to humid heat and, when molded into a product, has an excellent appearance after a humid heat test, as well as pellets, molded products, a method for improving appearance, and an appearance improving agent. [Modes for carrying out the invention]

[0012] The embodiments for carrying out the present invention (hereinafter simply referred to as "these embodiments") will be described in detail below. The embodiments described below are illustrative examples for explaining the present invention, i.e., examples of these embodiments, and the present invention is not limited to these. In this specification, "~" is used to mean including the numerical values described before and after it as the lower limit value and the upper limit value. "A~B" means A or more and B or less. Also, for any combination of the upper limit value and the lower limit value in this specification, it is cited as an example of this embodiment. In this specification, unless otherwise specified, various physical property values and characteristic values are those at 23°C.

[0013] [Resin Composition] The resin composition of this embodiment is a resin composition containing a thermoplastic resin and glass fiber, wherein the glass fiber contains C glass fiber and / or A glass fiber, and the thermoplastic resin contains a polyamide resin. By adopting such a configuration, it is possible to provide a resin composition that is excellent in heat and humidity resistance and has an excellent appearance after a heat and humidity test when formed into a molded product. Also, by blending glass fiber, a molded product excellent in mechanical properties such as tensile strength can be obtained.

[0014] [Mechanism] Regarding the mechanism of the effect of improving heat and humidity resistance according to the present invention, it is considered as follows.

[0015] Since the C glass fiber and / or A glass fiber constituting the recycled glass fiber have a large amount of alkali component, in a resin composition in which this is blended with a polyester resin such as polybutylene terephthalate or polyethylene terephthalate, which is considered preferable in Patent Document 4, when a heat and humidity test is performed on the obtained molded product, it is presumed that the carboxyl end of the polyester resin reacts with the alkali component contained in the C glass fiber and / or A glass fiber, generating an alkali metal salt, which becomes a powdery substance and deposits on the surface of the molded product, causing a poor appearance. Under such circumstances, in the resin composition of this embodiment, it is presumed that by blending a polyamide resin as the main component of the thermoplastic resin, the precipitation of such a powdery substance can be suppressed.

[0016] In the resin composition of the present embodiment, as components other than polyamide resin and C glass fiber and / or A glass fiber, at least one selected from the group consisting of styrenic resins, amorphous resins such as polycarbonate resin, elastomers, fillers such as talc, and flame retardants may be included. Even if the blending amount of these components is increased, it is difficult to have an adverse effect on the mechanical properties, appearance, etc. of the obtained molded product.

[0017] In addition, in the above-mentioned Patent Document 4, as a thermoplastic resin, there are examples of polyamide resin together with many other thermoplastic resins, but there is no description that polyamide resin is preferable. As described above, the preferable thermoplastic resins in Patent Document 4 are polybutylene terephthalate, polyethylene terephthalate, polycarbonate, and polyphenylene sulfide, and polybutylene terephthalate is used in the examples of Patent Document 4. Further, Patent Document 4 has no recognition of the problem of reduction in wet heat resistance due to recycled glass fiber or C glass fiber and / or A glass fiber.

[0018] <Thermoplastic resin> The thermoplastic resin contained in the resin composition of the present embodiment includes polyamide resin. The thermoplastic resin of the present embodiment can contain a plastic resin other than polyamide resin within a range that does not inhibit the effects of the present invention as necessary.

[0019] <<Polyamide resin>> Examples of the polyamide resin include aliphatic polyamide resin, semi-aromatic polyamide resin, and the like.

[0020] The aliphatic polyamide resin is not particularly limited, but is preferably at least one selected from polyamides containing diamines with 6 or more carbon atoms and / or dicarboxylic acids with 7 or more carbon atoms, and polyamides having a molecular structure obtained by ring-opening polymerization of caprolactams with 6 or more carbon atoms. Specifically, preferred aliphatic polyamide resins include polyamide 6, polyamide 11, polyamide 12, polyamide 4,10, polyamide 5,10, polyamide 6,10, polyamide 8,10, polyamide 9,10, polyamide 1010, and polyamide 1012, with polyamide 6, polyamide 6,6, polyamide 11, and polyamide 12 being more preferred. Polyamide 6 is even more preferred in particular because it also possesses impact resistance. The aliphatic polyamide resin may be a polyamide resin produced by ring-opening polymerization of various known lactams, or a polyamide resin produced by condensation polymerization of known aliphatic diamines and aliphatic dicarboxylic acids. Alternatively, an aliphatic polyamide made from raw materials derived from biomass resources may be used.

[0021] The semi-aromatic polyamide resin is not particularly limited, but examples include xylylenediamine-based polyamide resins comprising a diamine component such as metaxylylenediamine and / or paraxylylenemine, and an α,ω-linear aliphatic dicarboxylic acid component having 4 to 20 carbon atoms. Diamines other than meta-xylylenediamine and para-xylylenediamine that can be used as raw material diamine components for xylylenediamine-based polyamide resins include aliphatic diamines such as tetramethylenediamine, pentamethylenediamine, 2-methylpentanediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, dodecamethylenediamine, 2,2,4-trimethyl-hexamethylenediamine, and 2,4,4-trimethylhexamethylenediamine. Examples include alicyclic diamines such as 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, 1,3-diaminocyclohexane, 1,4-diaminocyclohexane, bis(4-aminocyclohexyl)methane, 2,2-bis(4-aminocyclohexyl)propane, bis(aminomethyl)decalin, and bis(aminomethyl)tricyclodecane, as well as aromatic ring-containing diamines such as bis(4-aminophenyl) ether, paraphenylenediamine, and bis(aminomethyl)naphthalene. These can be used individually or in combination of two or more. Biomass resource-derived raw material diamines may also be used. Preferred α,ω-linear aliphatic dicarboxylic acids having 4 to 20 carbon atoms for use as raw material dicarboxylic acid components in xylylenediamine-based polyamide resins include, for example, succinic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, adipic acid, sebacic acid, undecanediic acid, and dodecanediic acid. These can be used individually or in combination of two or more. Alternatively, raw material aliphatic dicarboxylic acids derived from biomass resources may also be used. Furthermore, examples of dicarboxylic acid components other than the above-mentioned α,ω-linear aliphatic dicarboxylic acids having 4 to 20 carbon atoms include phthalate compounds such as isophthalic acid, terephthalic acid, and orthophthalic acid, and isomers of naphthalenedicarboxylic acids such as 1,2-naphthalenedicarboxylic acid, 1,3-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 1,6-naphthalenedicarboxylic acid, 1,7-naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, and 2,7-naphthalenedicarboxylic acid, and can be used individually or in mixtures of two or more. Among semi-aromatic polyamide resins, polymeta-xylylene adipamide (polyamide MXD6) is a preferred choice.

[0022] The polyamide resin may be just one of these polyamide resins, or two or more may be mixed in any combination and ratio.

[0023] <<Other thermoplastic resins>> The resin composition of this embodiment may optionally contain other thermoplastic resins other than polyamide resins, as long as they do not impair the effects of the present invention.

[0024] While not particularly limited, other thermoplastic resins include, for example, polyethylene, polypropylene, polystyrene, polyvinyl chloride, vinyl polymers such as (meth)acrylic resins, ethylene-vinyl acetate copolymers, and ethylene-vinyl alcohol copolymers, polylactic acid resins, polyesters such as polyethylene terephthalate and polybutylene terephthalate, polyvinyl acetal resins such as polyvinyl acetal, polyvinyl benzal, and polyvinyl butyral resins, ionomer resins, polyphenylene ether, polyphenylene sulfide, polycarbonate, polyether ether ketone, polyacetal, ABS resin, LCP (liquid crystal polymer), fluororesin, urethane resin, silicone resin, various elastomers, or modified products of these resins.

[0025] For example, as mentioned above, the resin composition of this embodiment may also include other thermoplastic resins such as styrene resins and amorphous resins such as polycarbonate resins.

[0026] Examples of styrene-based resins include rubber-reinforced polystyrene or polystyrene. Rubber-reinforced polystyrene or polystyrene is preferably amorphous. Here, amorphous refers to the property that when a sample is measured using a differential scanning calorimeter (DSC) or the like, no clear melting point or melting peak is detected. Conversely, crystalline refers to the property that a crystalline structure in which molecules are regularly arranged is easily formed, and that a melting point and melting peak are detected by measurement using a differential scanning calorimeter (DSC) or the like. Syndiotactic polystyrene, in which benzene rings are regularly and alternately arranged on the polymer main chain, is crystalline and is preferably excluded from rubber-reinforced polystyrene or polystyrene.

[0027] As rubber-reinforced polystyrene, preferably a copolymer or blend of butadiene-based rubber components is used, and the content of the butadiene-based rubber component is usually 1% by mass or more and less than 50% by mass, preferably 3 to 40% by mass, more preferably 5 to 30% by mass, and even more preferably 5 to 20% by mass. High-impact polystyrene (HIPS) is particularly preferred as the rubber-reinforced polystyrene.

[0028] The polystyrene may be a homopolymer of styrene, or a copolymer of other aromatic vinyl monomers, such as α-methylstyrene, p-methylstyrene, vinyltoluene, vinylxylene, etc., in an amount of 50% by mass or less.

[0029] Any known polycarbonate resin can be used.

[0030] Polycarbonate resin is typically a branched thermoplastic polymer or copolymer obtained by reacting a dihydroxy compound, or a small amount thereof, with a polyhydroxy compound with phosgene or a diester carbonate. The method for producing polycarbonate resin is not particularly limited, and conventionally known methods such as the phosgene method (interfacial polymerization) or the melting method (transesterification) can be used.

[0031] As the raw material dihydroxy compound, aromatic dihydroxy compounds are preferred, including 2,2-bis(4-hydroxyphenyl)propane (i.e., bisphenol A), 2,2-bis(3-methyl-4-hydroxyphenyl)propane (i.e., bisphenol C), tetramethylbisphenol A, bis(4-hydroxyphenyl)-p-diisopropylbenzene, hydroquinone, resorcinol, 4,4-dihydroxydiphenyl, etc., with bisphenol A and / or bisphenol C being preferred. In addition, compounds in which one or more tetraalkylphosphonium sulfonates are bonded to the above aromatic dihydroxy compounds can also be used.

[0032] Among the polycarbonate resins mentioned above, aromatic polycarbonate resins derived from bisphenol A and / or bisphenol C, or aromatic polycarbonate copolymers derived from bisphenol A and / or bisphenol C and other aromatic dihydroxy compounds are preferred. Copolymers such as copolymers with polymers or oligomers having a siloxane structure may also be used. Furthermore, two or more of the above-mentioned polycarbonate resins may be mixed and used.

[0033] The silicone resin is not specifically defined; any known silicone resin can be used. The silicone resin is preferably a resin having repeating units of -Si(R)2-O- (where R is a hydrogen atom, a hydrocarbon group, or one of -O- hydrocarbon groups or -OH). R is preferably a hydrogen atom or a hydrocarbon group, and more preferably a hydrogen atom, a methyl group, or a phenyl group.

[0034] The resin composition of this embodiment may contain only one of the above-mentioned other thermoplastic resins as the thermoplastic resin, or it may contain two or more in any combination and any ratio.

[0035] <<Thermoplastic resin content>> The content of thermoplastic resin in the resin composition of this embodiment is preferably 50 parts by mass or more, more preferably 60 parts by mass or more, even more preferably 70 parts by mass or more, particularly preferably 75 parts by mass or more, and especially preferably 80 parts by mass or more, per 100 parts by mass of the resin composition. On the other hand, it is preferably 95 parts by mass or less, and more preferably 90 parts by mass or less. If the content of thermoplastic resin is above the lower limit, the moldability of the thermoplastic resin and the inherent effects of the thermoplastic resin are excellent. On the other hand, if the content of thermoplastic resin is below the upper limit, the glass fiber content can be relatively secured to improve mechanical strength. As described above, the resin composition of this embodiment may contain only one type of thermoplastic resin, or it may contain two or more types. When it contains two or more types, it is preferable that the total amount is within the above range.

[0036] The polyamide resin content in the resin composition of this embodiment is preferably 50 parts by mass or more, more preferably 60 parts by mass or more, even more preferably 70 parts by mass or more, particularly preferably 80 parts by mass or more, and especially preferably 85 parts by mass or more, per 100 parts by mass of the resin composition. On the other hand, it is preferably 95 parts by mass or less, and more preferably 90 parts by mass or less. If the polyamide resin content is above the lower limit, the effect of improving moisture and heat resistance due to the inclusion of polyamide resin is excellent. On the other hand, if the polyamide resin content is below the upper limit, the content of other components can be ensured, and the blending effect can be fully obtained. As described above, the resin composition of this embodiment may contain only one type of polyamide resin, or it may contain two or more types. When it contains two or more types, it is preferable that the total amount is within the above range.

[0037] If the resin composition of this embodiment contains a thermoplastic resin other than polyamide resin as the thermoplastic resin, it is preferable to adjust the ratio of polyamide resin to other thermoplastic resins so that the polyamide resin content in the resin composition of this embodiment falls within the above range. There are no particular restrictions, but the resin composition of this embodiment preferably contains 50% by mass or more of polyamide resin per 100% by mass of thermoplastic resin, more preferably 60% by mass or more, even more preferably 70% by mass or more, and particularly preferably 80-100% by mass.

[0038] <Glass fiber> The resin composition of this embodiment includes at least C glass fibers and / or A glass fibers as glass fibers.

[0039] The glass fibers used in this embodiment may be treated with a surface treatment agent or a sizing agent. When the glass fibers are treated with a surface treatment agent or a sizing agent, the content of the surface treatment agent and the sizing agent is preferably 0.01 to 1% by mass based on the glass fibers.

[0040] <<C glass fiber and / or A glass fiber>> C glass fiber and / or A glass fiber is a glass fiber containing more alkali metal components (usually sodium oxide and / or potassium oxide) than E glass fiber blended in a normal glass fiber reinforced thermoplastic resin composition, and the total of sodium oxide and / or potassium oxide is preferably 1% by mass or more, more preferably 2% by mass or more, still more preferably 5% by mass or more in the total 100% by mass of the C glass fiber and / or A glass fiber. On the other hand, the upper limit of the content of sodium oxide and / or potassium oxide in 100% by mass of the C glass fiber and / or A glass fiber is usually 20% by mass or less. In this embodiment, even when such glass fibers are used, the appearance of the obtained molded product after the wet heat test can be made good. In this embodiment, it is preferable to use recycled glass fiber as such C glass fiber and / or A glass fiber.

[0041] The recycled glass fiber of C glass fiber and / or A glass fiber may be a material recycled glass fiber or a mechanical recycled glass fiber, but is preferably a mechanical recycled glass fiber. In particular, A glass is the most widely used glass and is excellent in recycled resources.

[0042] Recycled glass fiber is contrasted with virgin glass fiber and is intended to include glass fiber obtained from defective products and end materials generated during the production of glass fiber in addition to once-marketed glass fiber.

[0043] C glass fibers and / or A glass fibers are preferably those with a number-average fiber length of 0.5 to 10 mm, and more preferably those with a number-average fiber length of 1 to 5 mm. By using glass fibers with such a number-average fiber length, the mechanical strength can be further improved. Here, the number-average fiber length of glass fibers is obtained by randomly selecting glass fibers to be measured from an image obtained by observing with an optical microscope, measuring their fiber lengths, and calculating the average of the obtained measurements. The observation magnification is 20x, and the number of measurements is 1,000 or more. This number-average fiber length roughly corresponds to the cut length of the fibers during spinning.

[0044] Furthermore, the cross-section of the C glass fiber and / or A glass fiber may be circular, elliptical, oblong, rectangular, a rectangle with semicircles on both short sides, cocoon-shaped, or any other shape, but circular is preferred. Here, "circular" includes not only a circular shape in the geometric sense, but also what is commonly referred to as circular in the technical field of this embodiment.

[0045] The number-average fiber diameter of C glass fibers and / or A glass fibers is preferably 4.0 μm or more at the lower limit, more preferably 4.5 μm or more, and even more preferably 5.0 μm or more. The upper limit of the number-average fiber diameter of the glass fibers is preferably 15.0 μm or less, and more preferably 14.0 μm or less. By using glass fibers having a number-average fiber diameter within this range, molded products with superior mechanical strength tend to be obtained. Here, the number-average fiber diameter of glass fibers is obtained by randomly selecting glass fibers to be measured from an image obtained by electron microscope observation, measuring the fiber diameter near the center, and calculating the average of the obtained measurements. The observation magnification is 1,000x, and the number of measurements is 1,000 or more. For glass fibers with a cross-section other than circular, the number-average fiber diameter is calculated as the number-average fiber diameter when converted to a circle with the same area as the cross-section.

[0046] The resin composition of this embodiment may contain only one type of C glass fiber and / or A glass fiber, or it may contain two or more types of different recycling methods, glass compositions, number-average fiber lengths, fiber diameters, etc., in any combination and any ratio. Note that C glass fiber and / or A glass fiber are not limited to recycled glass fiber, but may also be virgin glass fiber, but recycled glass fiber is preferred.

[0047] <<Other Fiberglass>> The resin composition of this embodiment may also contain glass fibers other than C glass fibers and A glass fibers.

[0048] For example, the resin composition of this embodiment may contain E glass fibers. E-glass fiber may be virgin glass fiber or recycled glass fiber.

[0049] If this embodiment includes glass fibers other than C glass fibers and / or A glass fibers, the preferred number-average fiber length, number-average fiber diameter, and cross-sectional shape of the other glass fibers are the same as those described above for C glass fibers and / or A glass fibers.

[0050] The resin composition of this embodiment may contain one other type of glass fiber, and may contain two or more types with different glass compositions, number-average fiber length, number-average fiber diameter, etc., in any combination and any ratio.

[0051] <<Glass fiber content>> In this embodiment, the glass fiber content is preferably 5 parts by mass or more, more preferably 8 parts by mass or more, even more preferably 10 parts by mass or more, particularly preferably 12 parts by mass or more, and especially preferably 15 parts by mass or more, per 100 parts by mass of the resin composition. On the other hand, it is preferably 95 parts by mass or less, more preferably 90 parts by mass or less, even more preferably 80 parts by mass or less, particularly preferably 70 parts by mass or less, and especially preferably 60 parts by mass or less, depending on the application. By setting the glass fiber content above the lower limit, the mechanical properties tend to improve further. Also, by setting the glass fiber content below the upper limit, the thermoplastic resin content is relatively maintained, and the moldability and the inherent effects of the thermoplastic resin tend to be superior. As described above, the resin composition of this embodiment may contain only one type of glass fiber, or it may contain two or more types. When it contains two or more types, it is preferable that the total amount is within the above range.

[0052] In this embodiment, the total content of C glass fibers and / or A glass fibers is preferably 1 part by mass or more, more preferably 3 parts by mass or more, even more preferably 5 parts by mass or more, particularly preferably 7 parts by mass or more, and especially preferably 10 parts by mass or more, per 100 parts by mass of the resin composition. On the other hand, it is preferably 40 parts by mass or less, more preferably 35 parts by mass or less, even more preferably 30 parts by mass or less, particularly preferably 25 parts by mass or less, and especially preferably 20 parts by mass or less, depending on the application. By setting the content of C glass fibers and / or A glass fibers to be above the lower limit above, the mechanical properties tend to improve further. Furthermore, by setting the content of C glass fibers and / or A glass fibers to be below the upper limit above, the effect of suppressing appearance defects after humid and heat resistance tends to be more pronounced. As described above, the resin composition of this embodiment may contain only one type of C glass fiber and / or A glass fiber, or it may contain two or more types. When two or more types are included, it is preferable that their total amount be within the above range.

[0053] If the resin composition of this embodiment contains glass fibers other than C glass fibers and A glass fibers as glass fibers, it is preferable to adjust the content ratio of C glass fibers and / or A glass fibers to other glass fibers so that the content of C glass fibers and / or A glass fibers in the resin composition of this embodiment falls within the above range. There are no particular restrictions, but the resin composition of this embodiment preferably contains 10% by mass or more of C glass fibers and / or A glass fibers per 100% by mass of glass fibers, more preferably 15% by mass or more, even more preferably 25% by mass or more, and particularly preferably 30 to 100% by mass.

[0054] In the resin composition of this embodiment, it is preferable that the resin composition contains 1% by mass or more of recycled glass fibers relative to 100% by mass of the total amount of C glass fibers and A glass fibers contained in the resin composition. This content may be 10% by mass or more, 30% by mass or more, 50% by mass or more, 70% by mass or more, or 90-100% by mass.

[0055] The resin composition of this embodiment can be configured to be substantially free of glass fibers other than C glass fibers and A glass fibers. "Substantially free of glass fibers other than C glass fibers and A glass fibers" means that the content of glass fibers other than C glass fibers and A glass fibers in the resin composition of this embodiment is less than 10% by mass per 100% by mass of the resin composition, preferably less than 5% by mass, and more preferably less than 1% by mass.

[0056] The resin composition of this embodiment may or may not contain virgin glass fibers. The resin composition of this embodiment may also be configured to be substantially free of virgin glass fibers. Substantially free of virgin glass fibers means that the virgin glass fiber content in the resin composition of this embodiment is less than 5% by mass of 100% by mass of the resin composition, and this content is preferably less than 3% by mass, and more preferably less than 1% by mass.

[0057] If the resin composition of this embodiment contains E glass fibers, the content is preferably 1 to 50 parts by mass, and more preferably 1 to 30 parts by mass, based on 100 parts by mass of the total content of glass fibers and / or A glass fibers contained in the resin composition. The resin composition of this embodiment can be substantially free of E-glass fibers. Substantially free of E-glass fibers means that the E-glass fiber content in the resin composition of this embodiment is less than 10% by mass of 100% by mass of the resin composition, and this content is preferably less than 5% by mass, and more preferably less than 1% by mass.

[0058] <Other ingredients> The resin composition of this embodiment may contain other components besides thermoplastic resin and glass fiber, as needed, as long as they do not significantly impair the desired physical properties. The other components may be present as a single component, or as two or more components in any combination and ratio. Other examples of components include thermosetting resins, resin additives, and fillers other than the glass fibers mentioned above.

[0059] Examples of resin additives include reactive compounds, stabilizers (heat stabilizers, light stabilizers), flame retardants, flame retardant aids, anti-dripping agents, transesterification inhibitors, UV absorbers, mold release agents, colorants (pigments, dyes), nucleating agents, antistatic agents, anti-fogging agents, anti-blocking agents, flow improvers, plasticizers, and dispersants. The total content of these other components is preferably 0% by mass or more and less than 10% by mass, more preferably 0% by mass or more and less than 5% by mass, and even more preferably 0% by mass or more and less than 3% by mass, based on 100% by mass of the resin composition.

[0060] <Recycling rate> The resin composition of this embodiment preferably has a high recycling rate. Specifically, the proportion of recycled material is preferably 10 parts by mass or more, more preferably 20 parts by mass or more, even more preferably 30 parts by mass or more, particularly preferably 40 parts by mass or more, especially preferably 50 parts by mass or more, and may be 60 parts by mass or more, 70 parts by mass or more, 80 parts by mass or more, or even 90 parts by mass or more. Furthermore, some or all of the thermoplastic resin may be recycled thermoplastic resin.

[0061] <Method for producing resin compositions> The resin composition of this embodiment can be manufactured according to conventional methods for manufacturing resin compositions (e.g., pellets). Typically, each component and various additives added as desired are thoroughly mixed, and then melt-kneaded in a single-screw or twin-screw extruder. Alternatively, the resin composition of this embodiment can be manufactured by supplying the components to the extruder using a feeder and melt-kneading them without pre-mixing them, or by pre-mixing only a portion of them. For example, for glass fibers, it is preferable to supply them to the extruder using a side feeder and melt-knead them. Alternatively, some components may be melt-kneaded with a thermoplastic resin to prepare a masterbatch, and then the remaining components may be added to this and melt-kneaded. The resin composition of this embodiment can be pelletized according to a conventional method in the later stage of the melt-kneading process to obtain the pellets of this embodiment.

[0062] [Molded products] The resin composition of this embodiment, or the pellets of this embodiment obtained by pelletizing the resin composition of this embodiment according to a conventional method, can be molded according to a known method to obtain the molded article of this embodiment.

[0063] The method for manufacturing the molded article of this embodiment is not particularly limited, and any molding method commonly used for thermoplastic resin compositions can be arbitrarily employed. Examples include injection molding, ultra-high-speed injection molding, injection compression molding, two-color molding, hollow molding methods such as gas-assisted molding, molding using a heat-insulating mold, molding using a rapidly heated mold, foam molding (including supercritical fluid), insert molding, IMC (in-mold coating) molding, extrusion molding, sheet molding, thermoforming, rotational molding, lamination molding, press molding, blow molding, etc., with injection molding being preferred among them. Details of the injection molding method can be found in paragraphs 0113 to 0116 of Japanese Patent No. 6183822, and these contents are incorporated herein by reference. Furthermore, the mold temperature during mold molding, such as injection molding, is preferably between 40 and 150°C.

[0064] [Application] The resin composition or pellets of this embodiment are used as molding materials for the molded articles of this embodiment. The molded articles of this embodiment can be widely used in known applications. For example, they can be widely used both indoors and outdoors in materials for electrical and electronic equipment, automotive materials, housing materials, and materials for manufacturing parts in other industrial fields. More specifically, examples include circuit breakers, electromagnetic switches, various relay components, transformer components, sensor components, switch components, connector components, terminal components, actuator components, outlet components, socket components, plug components, capacitor components, resistor components, charging components, battery components, housing components, structural components, and insulating components. In particular, it can be suitably used as a material for components located near electrical contacts.

[0065] Automotive materials include housings, reflectors, bezels, and extensions for lamps, as well as connectors, ECU cases, enclosures for in-vehicle cameras and millimeter-wave radar, battery cases, and sensor enclosures. Examples of electrical and electronic components include various housings, personal computers, game consoles, display devices such as televisions, printers, copiers, scanners, fax machines, electronic organizers and PDAs, electronic desktop calculators, electronic dictionaries, cameras, video cameras, mobile phones, battery packs, drives and readers for recording media, mice, numeric keypads, housings, covers, keyboards, buttons, and switch components for CD players, MD players, portable radios and audio players, power meter housings, battery cases, battery transport trays, relays, sensors, actuators, terminal switches, and components for grill cooking equipment.

[0066] [How to improve appearance] The method for improving the appearance of the thermoplastic resin and a resin composition containing C glass fibers and / or A glass fibers is characterized in that at least a portion of the thermoplastic resin is made of polyamide resin.

[0067] Here, the thermoplastic resin, polyamide resin, C glass fiber and / or A glass fiber, and resin composition described above in the description of the resin composition of this embodiment apply.

[0068] In the method for improving appearance of this embodiment, in a resin composition containing a thermoplastic resin and C glass fibers and / or A glass fibers, by using a polyamide resin as at least a portion of the thermoplastic resin, the problem of reduced heat resistance due to alkaline components such as sodium oxide and / or potassium oxide in the C glass fibers and / or A glass fibers can be mitigated, and mechanical strength can be improved by the blending of C glass fibers and / or A glass fibers, thereby providing a resin composition and molded articles thereof with excellent appearance after a heat test.

[0069] [Appearance enhancer] The appearance-enhancing agent of this embodiment is an appearance-enhancing agent for a resin composition containing a thermoplastic resin and C glass fibers and / or A glass fibers, and is characterized by containing a polyamide resin.

[0070] Here, the thermoplastic resin, polyamide resin, C glass fiber and / or A glass fiber, and resin composition are described in the above-mentioned description of the thermoplastic resin, polyamide resin, C glass fiber and / or A glass fiber, and resin composition in this embodiment. However, the thermoplastic resin in the resin composition to which the appearance enhancer of this embodiment is applied contains a thermoplastic resin other than polyamide resin. According to the appearance enhancer of this embodiment, by adding an appearance enhancer containing polyamide resin, preferably an appearance enhancer made of polyamide resin, to a resin composition containing such a thermoplastic resin other than polyamide resin and C glass fiber and / or A glass fiber, the problem of reduced heat resistance due to alkaline components such as sodium oxide and / or potassium oxide in the C glass fiber and / or A glass fiber can be mitigated, and mechanical strength can be improved by the blending of C glass fiber and / or A glass fiber, thereby providing a resin composition and molded articles with excellent appearance after a heat test.

[0071] The appearance-enhancing agent of this embodiment may also be provided as a glass fiber masterbatch containing polyamide resin and C glass fibers and / or A glass fibers. In this case, C glass fibers and / or A glass fibers such as recycled glass fibers and polyamide resin can be blended into various thermoplastic resins as a recycled glass fiber masterbatch containing 10 to 90 parts by mass of polyamide resin and 90 to 10 parts by mass of C glass fibers and / or A glass fibers per 100 parts by mass of the total of these, thereby improving the mechanical strength of the resin composition without impairing its moisture and heat resistance. [Examples]

[0072] The present invention will be described in more detail below with reference to examples. The materials, amounts used, proportions, processing content, and processing procedures shown in the following examples can be modified as appropriate, as long as they do not depart from the spirit of the present invention. Therefore, the scope of the present invention is not limited to the specific examples shown below. If the measuring instruments used in the examples are difficult to obtain due to discontinuation or other reasons, measurements can be taken using other instruments with equivalent performance.

[0073] 1.Raw materials In the following examples and comparative examples, the raw materials shown in Table 1 were used.

[0074] [Table 1]

[0075] [Example 1, Comparative Example 1] <Manufacturing of thermoplastic resin compositions> Each component shown in Table 1 was used in the proportions shown in Table 2, and all components except the glass fibers were uniformly mixed in a tumbler mixer. The resulting mixture was supplied to a twin-screw extruder (TEX30α, manufactured by Japan Steel Works, Ltd.) through the main feed port. The cylinder temperature in the first kneading section was set to 260°C, and the glass fibers were supplied from the side feeder. After the addition of the glass fibers, the cylinder temperature was set to 220°C, and the resin composition, which was melt-kneaded at a screw rotation speed of 200 rpm, was rapidly cooled in a water bath and pelletized using a pelletizer to obtain pellets of the resin composition. In Comparative Example 1, polybutylene terephthalate (PBT) is combined with an epoxy resin to improve heat and humidity resistance and an antioxidant to improve thermal stability.

[0076] <Forming of test specimens> The pellets of the thermoplastic resin composition obtained above were dried at 120°C for 5 hours, and then JIS K7139 multipurpose test specimens (4 mm thick) were injection molded using an injection molding machine (Japan Steel Works "J-85AD-60H") under the conditions of a cylinder temperature of 265°C and a mold temperature of 80°C. The obtained multipurpose test specimens (4 mm thick) were treated for 25 hours using a pressure cooker tester (ESPEC "EH8-221M") under the conditions of a temperature of 121°C, relative humidity of 100%, and pressure of 2 atm. The test specimens were visually inspected after 25 hours of treatment and evaluated as follows. A: The test specimen maintained a good appearance. B: A small amount of powdery material was observed on the surface of the test specimen, but it was at a practical level. C: Powdery material was observed on the surface of the test specimen. The results are shown in Table 2.

[0077] [Table 2]

[0078] As is clear from Table 2, in the molded articles of the resin composition of this embodiment, in which polyamide resin was used as the thermoplastic resin, no powdery material precipitated after the moist heat test, and an excellent appearance was observed. In contrast, the molded article of Comparative Example 1, which did not use polyamide resin as the thermoplastic resin, had an inferior appearance due to the precipitation of powdery material.

[0079] Although the present invention has been described in detail using specific embodiments, it will be apparent to those skilled in the art that various modifications are possible without departing from the intent and scope of the present invention.

Claims

1. A resin composition comprising a thermoplastic resin and glass fibers, The glass fiber includes C glass fiber and / or A glass fiber, A resin composition in which the thermoplastic resin includes a polyamide resin.

2. The resin composition according to claim 1, wherein the glass fibers include recycled glass fibers.

3. The resin composition according to claim 1, wherein the C glass fiber and / or A glass fiber contains 1% by mass or more of sodium oxide and / or potassium oxide.

4. Pellets of the resin composition according to any one of claims 1 to 3.

5. A molded article formed from the resin composition described in any one of claims 1 to 3.

6. A molded article formed from the pellets described in claim 4.

7. A method for improving the appearance of a resin composition comprising a thermoplastic resin and C glass fibers and / or A glass fibers, wherein at least a portion of the thermoplastic resin is made of polyamide resin.

8. An appearance-enhancing agent for a resin composition comprising a thermoplastic resin and C glass fibers and / or A glass fibers, the appearance-enhancing agent comprising a polyamide resin.

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